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tance to the cane industry, as they show that a cheap and easily-managed apparatus 

 for evaporating at a low temperature, suited to the use of thousands of small facto- 

 ries, may be found in machines for drying or evaporating semi-sirup by hot air ; and 

 the method seems peculiarly adapted to the dry air of the Western States and Terri- 

 tories. 



The first form of apparatus we used consisted of a liquid-carrier, which had 322 

 square feet of surface, inclosed in a box or case 3 feet wide by 2 feet, and 14 feet 

 high, placed upon a square tank which held 300 gallons of sirup. The liquid-carrier 

 passed continuously through the sirup in the tank, and its 322 square feet of surface 

 were kept uniformly wet with sirup in thin films by the adhesion of sirup to the 

 surfaces. A fan forced a blast of air through all the surfaces of the liquid-carrier. 

 Hot sirup from the finishing pan was run into the tank, and was immediately spread 

 over the 322 square feet of surface on the liquid-carrier by the motion of the liquid- 

 carrier, where it came in contact with the current of air. The result was that con- 

 siderable water escaped from the hot sirup in the form of steam, instead of condens- 

 ing in the sirup, as it does when hot sirup is cooled in the ordinary way, and this 

 increased the density of the sirup. The blast of air also absorbed and carried off con- 

 siderable water from the sirup, and the density of the sirup was thus increased three or 

 four degrees by the Baum6 saccharometer. This was equivalent to boiling the sirup to 

 greater density without the injury caused by the excessive heat necessary in boiling 

 heavy sirup. The sooner sirup is removed from the heat of the finishing pan the 

 better it is, and the sooner hot sirup is cooled the better it is, for finished sirup is 

 hot enough to be injured by the heat it contains after it has left the finishing pan. 

 The output of the Sterling Sirup Works is 2 to 3 barrels per hour, and in previous 

 years we have had trouble and loss in cooling that quantity of sirup in steady day 

 and night runs. The above-described apparatus cools hot sirup in large quantities, 

 and also increases its density quickly and perfectly. It reduced the temperature of 

 100 gallons of boiling sirup from 236 degrees to 110 degrees in five minutes. 



In boiling sirup we usually boil until the sirup has a density while hot of 35 to 36 

 degrees, as tested by the Baume" saccharometer, but after testing this apparatus we 

 boiled only to 30 degrees, and then reduced it to the proper density by leaving it in 

 this apparatus exposed to the blast of air until it becomes as dense as if it had been 

 boiled to 36 degrees and had then been cooled in the ordinary \vay. We regard it as 

 an established fact, that sirup at 30 Baume can be evaporated on large surfaces by 

 air to any density required, and also th.it the color and flavor of the sirup are better 

 than when exposed longer to the high heat of the finishing pan. By allowing the 

 sirup to remain for some time in this apparatus the sirup was evaporated or dried by 

 the current of air to such density that it was impossible to draw the sirup from the 

 tank through a 2-inch outlet until it had been diluted. All the sirup made this sea- 

 son from 700 acres of cane was cooled ready to barrel and was finished from densities 

 varying from 30 Baum6 to 36 Ban me* by air evaporation in this apparatus. We next 

 built an apparatus on the same plan as the above-described apparatus, except that it 

 had no fan to cause a current of air ; the current of air was caused by heating the air 

 in a furnace, as is done in hot-air fruit evaporators. Hot air evaporates water much 

 more rapidly than cold air, and in operating on thin or dilute sweet liquids it is nec- 

 essary to heat the air above the fermenting point above the point where air has 

 chemical action on the liquid. This is shown by drying fruit in air at summer tem- 

 perature ; the product is the inferior sun-dried fruit, because the air has acted chem- 

 ically on the saccharine liquid in the fruit; but when fruit is dried by hot air, as in 

 the modern fruit-evaporators, the product is perfect, because hot air has no chemical 

 action on the sweet liquid in the fruit. This hot-air apparatus had 273 square feet of 

 surface covered with semi-sirup in thin films, and exposed to a current of hot air which 

 absorbed and carried off the water of the sirup. In this apparatus cane juice which 

 had been boiled until the scum was white and free from green color was evaporated 



